Figure REF  shows details of the trailing edges of DSWs on either side of the predicted onset of modulational
instability at \(u_{+} = 0.84375\) . It can be seen that there is some non-uniform modulation of the trailing edges, with
a modulated wavepacket, but there is no distinct change in the behaviour of the DSW, as found for other DSWs for
which the admissibility conditions are not satisfied [1]}, [2]}. The reason for this is the highly nonlocal
response of the nematic. It has been shown theoretically and verified experimentally that high nonlocality acts to suppress
modulational instability [3]}, [4]}. This greatly delays the onset of instability, so much so that
theoretically unstable nematic wavetrains show no instability over experimental propagation distances (\(\sim 1mm\) ).
<FIGURE>